docs: rewrite README + add CI/Codecov

[Snider]

Summary

• Rewrote README to reflect current API (DI framework, not old CLI/GUI)
• Added GitHub Actions CI workflow — runs tests with coverage on push to main
• Codecov badge pointing at dAppCore/core

Test plan

• CI workflow runs after merge
• Codecov badge updates on README

Co-Authored-By: Virgil virgil@lethean.io

Summary by CodeRabbit

Release Notes

• Chores

  • Added GitHub Actions CI workflow for automated testing and code coverage reporting to Codecov.

• Documentation

  • Revised README with a new "Core" library overview, updated installation instructions, simplified usage examples covering service registration and command setup, and documentation for managed service lifecycle and IPC messaging primitives.

[coderabbitai]

Caution

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Run ID: d457b686-c2ef-4abe-a9c8-9e40055e92bf

📥 Commits

Reviewing files that changed from the base of the PR and between 3bf175b and 01135ac.

📒 Files selected for processing (2)

• .github/workflows/ci.yml
• README.md

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📝 Walkthrough

Walkthrough

Added a GitHub Actions workflow for continuous integration that runs tests and uploads coverage reports to Codecov on pushes to main. Substantially rewrote README documentation, replacing detailed architecture and build guides with a minimal library overview including usage examples, service registration, and IPC patterns.

Changes

Cohort / File(s)	Summary
Continuous Integration .github/workflows/ci.yml	Created new GitHub Actions workflow that runs on main branch pushes, executing Go tests with coverage output and uploading results to Codecov.
Documentation README.md	Completely restructured README from detailed architecture guide to minimal Core library overview. Removed configuration/build/CLI documentation; added Quick Start, service registration, command registration, primitives, result abstraction, managed service lifecycle, and IPC/message bus examples.

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